I've been trying my hand a wines and fruit wines for a few years now. I keep running into a similar problem where I still have dissolved CO2 even after months in bulk aging.
I assume it's ready, schedule bottling day, get everything ready, taste the wine and Bam! Bubbles with stale yeast farts!
Here's how it goes...
I usually leave in primary for 2-3 weeks allowing most of the sediment to fall. Rack into glass, and bulk age for 3-12 months. I only rack again in that time if there are significant lees above 1/4". Aging storeroom is 60°F-64°F almost year round.
Last fall I had a Concord wine aged 12 months since primary and it was still so carbonated. Ended up agitating and warming to over 72°F to get it to go flat. Today I just had a chardonnay from a juice kit that had been aging for 3 months, 4 from start of primary. I know that's a little soon, but I wanted to finish in bottles to free up a carboy.
What do you do and what do I need to change to have better degassing?
I KNOW THE HEADSPACE. This is for less than a day. I used the 6 gallon plastic carboy for agitating.